In recent broadband wireless communication systems, installing more femto Base Stations (BSs) to complement a macro BS is considered. The femto BS is used as a home BS or a Small Office Home Office (SOHO) BS, which is installed in a region outside the coverage of the macro BS or a region where service quality is poor due to weak signal strength. The femto BS is classified into an office BS and an enterprise BS. Similarly to the macro BS, the femto BS provides a portable Internet service to a Mobile Station (MS). The femto BS is characterized by low power, small throughput, inexpensive cost, and so forth, which are optimized for a small-sized indoor environment such as home or SOHO.
Due to the characteristic (i.e., low power, small throughput, inexpensive cost, and so forth) of the femto BS, it is expected that the number of BSs to be installed will increase exponentially. Accordingly, persistent network optimization is required for frequent installation and removal of the femto BS. As a result, a function of automatically installing a BS to reduce network installation cost and a function of reading and applying configuration changes of neighbor femto BSs are required. For this, a standardization work named as a self organization network or a self configuration network is currently being conducted for a next generation mobile communication standard.
A femto BS that includes a function of automatic BS installation and a function of automatic network optimization has to provide an MS with a service by adaptively determining a Frequency Allocation (FA) for use, Transmit (Tx) power, a cell IDentifier (ID), and so forth, according to an installation environment, so that the femto BS can adaptively operate in a neighbor wireless environment during initial installation or operation.
Since the femto BS can operate according to the same system protocol as the macro BS, interference to a macro cell has to be negligible or minimized as much as possible. When a large number of femto BSs are installed without satisfying this requirement, the macro BS may be affected by interference caused by the femto BSs, and thus may not be able to properly operate.
Accordingly, there is a need for a method of automatically selecting an FA to minimize an influence on a macro cell while maximizing a throughput of a femto BS.